Three component 2.5x microscope objective

ABSTRACT

A three component achromatic microscope objective having a magnification of 2.5X and a numerical aperture of 0.07.

OR 3,659,925 f United State:

Shoemaker [54] THREE COMPONENT 2.5x MICROSCOPE OBJECTIVE [72] Inventor: Arthur H. Shoemaker, Erie. NY.

[73] Assignee: American Optical Corporation,

Southbridge, Mass.

22 Filed: Mar. 24, 1971 [21] Appl. No.: 127,571

[52] U.S. Cl. ..350/225, 350/175 ML [51] Int. Cl. ..G02b 21/02 [58] Field olSearch ..350/225, I75 ML i parallel Ilqhl m1 3,659,925 51 May2, 1972 References Clted UNITED STATES PATENTS 2,713,808 7/1955 Klein ..350/l75 ML UX 3,262,363 7/1966 Ziegler ..350/225 Primary Examiner-John K. Corbin Attorney-William C. Nealon, Noble S. Williams, Robert I. Bird and Bernard L. Sweeney ABSTRACT A three component achromatic microacope objective having a magnification of 2.5x and a numerical aperture of 007.

2 Claim, 1 Drawing Figure Patented May 2, 1972 1 parallel l llqhl III ARTHUR H. SHOEMAKER BY a) w ATTORNEY THREE COMPONENT 2.5K MICROSCOPE OBJECTIVE BACKGROUND OF THE INVENTION This invention relates to improvements in a microscope objective, and in particular to an achromatic microscope objecjective are listed in the following table in which ND is the refractive index for the D line of sodium,-y is the Abbe number. Radii (R), thicknesses (T), and spacings (S) are expressed in millimeters and a negative sign indicates radii on 5 centers of curvature lying on the object side of their vertices.

MAGNIFICATION=2.5 N.A. =0.07

tive with a magnification of substantially 2.5x and a numerical aperture of substantially 0.07. lt is the object of the present invention to provide such a microscope objective which is well corrected for the usual chromatic image aberrations as well as spherical aberration, coma, and astigmatism, while having a substantially flat image field when used with a telescope objective as described in U. S. Pat. No. 3,355,234, issued to Robert M. Muller.

The foregoing parameters of radius, thickness, and spacing 30 are functions of the equivalent focal length F of the objective.

The value of F, as an example, is 72.986 millimeters. At this focal length, the absolute values of the foregoing data are as follows:

F=72.986 MAGNIFICATION =2.5X N.A.=0.07

The drawing is an optical diagram of a microscope objective of the present invention.

DESCRIPTION Referring now to the drawing, a microscope objective is shown generally at 2. It includes the following components: A

from single lens 4, a doublet 6, and a doublet 8, all of said 65 components being optically aligned. Objective 2 is shown disposed relative to an object plane 10 supporting a specimen or object 12. Lens 4 is a plano-concave lens, also designated I. Doublet 6 includes a double convex lens element II and a double concave lens element lll, together forming a convex-con- 70 cave doublet. Doublet 8 includes a double concave lens ele ment IV and a double convex lens element V, together forming a concave-convex doublet.

The parameters of the lens elements which make up the ob- I. An achromatic microscope objective having a magnification of substantially 2.5x and a numerical aperture of substan- 60 tially 0.07 for forming an image of an object plane, said image being determined by the following relationship wherein said second and third elements forming a doubleta fourth double concave lens element IV;

2. An achromatic microscope objective having a magnification of substantially 2.5X and a numerical aperture of substantially 0.07 for forming an image of an object plane, said image being well corrected for chromatic and spherical aberrations, coma, astigmatism, and curvature of image field, said objective comprising the following components:

a front piano-concave lens I;

a fifth double convex lens element V;

said fourth and fifth elements forming a doublet;

all of said components being optically aligned;

the parameters of lens radii (R), thicknesses (T), spacings (S), refractive indices (ND), and Abbe numbers (7), being determined by the following relationship wherein radii, thicknesses, and spacings are expressed in millimea second double convex lens element ll; ters: a third double concave lens element ll];

r'=72.986 MAGNIFICATION=Z5X N.A.=0.07

Lens Radius R Thickness T Space 8 Refractive Abbe index ND Number r 81:9.480 R|=Plano I T1=l.500 ND1=1.6966J vl=56.l3

S2=5.84 R;=19.610 II T1=2.326 ND2=L7l7l5 w2=29.51

R4=4.343 IiI TJ=L090 N1)3=1.s4316 v3=47.92

S3=HA70 Ra= -100.160 IV T4=L500 ND4=L74054 =27.

R7=15.500 V T5=3A63 ND5=L69669 r5=56.13

t i i U 

1. An achromatic microscope objective having a magnification of substantially 2.5X and a numerical aperture of substantially 0.07 for forming an image of an object plane, said image being well corrected for chromatic and spherical aberrations, coma, astigmatism, and curvature of image field, said objective comprising the following components: A FRONT PLANO-CONCAVE LENS I; a second double convex lens element II; a third double concave lens element III; said second and third elements forming a doublet; A FOURTH DOUBLE CONCAVE LENS ELEMENT IV; a fifth double convex lens element V; said fourth and fifth elements forming a doublet; ALL OF SAID COMPONENTS BEING OPTICALLY ALIGNED; THE PARAMETERS OF LENS RADII (R), thicknesses (T), spacings (S), refractive indices (ND), and Abbe numbers ( gamma ), being determined by the following relationship wherein radii, thicknesses, and spacings are expressed in millimeters:
 2. An achromatic microscope objective having a magnification of substantially 2.5X and a numerical aperture of substantially 0.07 for forming an image of an object plane, said image being well corrected for chromatic and spherical aberrations, coma, astigmatism, and curvature of iMage field, said objective comprising the following components: a front plano-concave lens I; a second double convex lens element II; a third double concave lens element III; said second and third elements forming a doublet; a fourth double concave lens element IV; a fifth double convex lens element V; said fourth and fifth elements forming a doublet; all of said components being optically aligned; the parameters of lens radii (R), thicknesses (T), spacings (S), refractive indices (ND), and Abbe numbers ( gamma ), being determined by the following relationship wherein radii, thicknesses, and spacings are expressed in millimeters: 